Mint gets about $30 to $40 to refer its users to banking and credit products from banks it partners with. (Mint figures out which cards/accounts could save you the most money, etc.)

About 10% to 15% of Mint users end up generating a lead. (Patzer says that people are applying for more credit cards these days than they used to, but are getting approved for fewer.)

We are guessing that Mint has signed up about 300,000 users so far this year, so its net users signed up in 2009 could be 1.8 million to 2.3 million. Assuming 12.5% of them take a credit or banking service that brings in $35 each for Mint, that's about $8 million to $10 million in 2009 sales.

That could go up or down, of course, depending on growth rates, banks' marketing budgets, etc. Mint plans to add more products, including CDs and brokerages to its recommendation engine, which could boost revenues. But who knows what's going to happen to banks as the recession continues.

With about 30 employees, we estimate Mint has all-in costs around $4 million to $5 million at its current size. We assume it will grow pretty rapidly this year, so $10 million in sales could be a breakeven year or a small profit or loss. Either way, Mint does not appear to be burning cash.

What's the exit? With a big enough user base, we think Mint could be an attractive acquisition target for any big Web portal, such as Yahoo, Google, AOL, or Microsoft. Or maybe a bank will buy it for its technology. The company has raised more than $17 million in financing from Benchmark Capital, Shasta Ventures, First Round Capital, and angel investors.